DF-1629

OpRegion KVA mappings leak on every suspend/resume: pmap_mapbios mappings invisible to DRM iounmap()

Summary

intel_opregion.c:987 pmap_mapbios(asls,OPREGION_SIZE) header mapping. 1031 pmap_mapbios(rvda,rvds) RVDA mapping. Neither registered in DRM iomap_list (only __ioremap_common populates). intel_opregion_unregister:832/834 iounmap(header/rvda) -> linux_iomapping.c:61-78 SLIST search finds nothing -> prints iounmap: invalid address -> returns WITHOUT pmap_unmapdev. KVA leak per suspend/resume: 8KB header + rvds RVDA. After enough cycles kernel_map exhausted -> pmap_mapdev panic. Trigger: acpiconf -s3 loop or kldunload/kldload drm. Fix: save rvds_size + pmap_unmapdev in unregister.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U:C:N/I:N/A:L
CWE: CWE-401 Missing Release of Memory after Effective Lifetime
File: sys/dev/drm/i915/intel_opregion.c
Lines: 987-834
Area: dev
Discovered: 2026-07-18
Updated: 2026-07-18

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: likely
Tested: 2026-07-23 17:00:09
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 17:00:09
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1629/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1629 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	429 B	view raw
VERDICT.md	verdict	source-confirmation analysis	713 B	↓ raw
build.sh	build-script	N/A (source-only)	61 B	view raw
run.sh	run-script	N/A (source-only)	87 B	view raw

VERDICT.md verdict source-confirmation analysis

↓ download raw

DF-1629 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: intel_opregion.c:987 pmap_mapbios(asls,OPREGION_SIZE) header mapping. 1031 pmap_mapbios(rvda,rvds) RVDA mapping. Neither registered in DRM iomap_list (only __ioremap_common populates). intel_opregion_

Citation: sys/dev/drm/i915/intel_opregion.c:987-834

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: OpRegion KVA mappings leak on suspend/resume (intel_opregion.c:987,832-834)

Verified recommended fix

Source-confirmed: OpRegion KVA mappings leak on suspend/resume (intel_opregion.c:987,832-834)

Verdict

Source-confirmed: OpRegion KVA mappings leak on suspend/resume (intel_opregion.c:987,832-834)